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Ilhang SHIN(Ilhang SHIN),Inkyung YOON(Inkyung YOON),Hansol LEE(Hansol LEE) 한국유통과학회 2023 유통과학연구 Vol.21 No.4
Purpose: Research on the valuation of the e-commerce distribution companies is necessary because the traditional valuation methodology cannot be easily applied. Considering the valuation and initial public offering (IPO) of Coupang, Korea’s leading ecommerce company, this study contributes to the literature by examining various valuation methods applicable to corporate valuation in the e-commerce industry and provides their implications. Research design, data and methodology: This case study investigates research, analyst reports, news articles, and magazines to review the valuation methods for companies in the e-commerce industry and analyzes the case of the Coupang IPO. Results: A valuation method that considers growth potential, which is important for companies in the e-commerce industry, is used for IPOs. This led to Coupang’s successful IPO on the New York Stock Exchange despite its accumulated losses. However, the continued price decline since listing suggests that Coupang’s valuation should have considered more factors. Conclusions: This study provides guidelines for the valuation of companies in the e-commerce industry, which eventually improves the overall industry. Moreover, this study provides directions for improving the valuation methods for e-commerce firms.
Shin, Hansol,Kim, Tae Hyun,Kim, Hyoungtae,Lee, Sungwoo,Kim, Wook ELSEVIER 2019 APPLIED ENERGY -BARKING THEN OXFORD- Vol.252 No.-
<P><B>Abstract</B></P> <P>Recently, concerns about greenhouse gas reduction in the power generation sector have increased significantly. The introduction of environmental economic dispatch is being discussed in depth, particularly in countries where there is insufficient investment in fundamental greenhouse gas mitigation measures, such as renewable energy, or carbon capture and storage. The most significant problem with the existing environmental economic dispatch studies for greenhouse gas reduction is that they do not consider the time horizon difference between the greenhouse gas emission target (allocated on an annual basis) and environmental economic dispatch formulation (optimized on an hourly basis). Most of the existing environmental economic dispatch studies assume that hourly greenhouse gas emission targets are given, or if they are formulated as an annual optimization problem, they only deal with relatively small systems. In this paper, we propose a novel environmental shutdown method that can find the near optimal solution to the environmental economic dispatch problem for greenhouse gas reduction, simultaneously considering the hourly allocation problem and environmental economic dispatch optimization. In order to verify the effectiveness of the proposed method, it is applied to a large-scale power system with actual system and technical parameters. As a result, the proposed method is considered to be one of the effective methods of environmental economic dispatch that can be used to achieve short-term greenhouse gas reduction targets in countries where investment in renewable energy is not sufficient.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hourly economic dispatch problem with annual CO<SUB>2</SUB> emission constraint is solved. </LI> <LI> The problem is complicated due to two different time horizons. </LI> <LI> Environmental shutdown method is proposed to find the near optimal solution. </LI> <LI> It is confirmed that the proposed method works well for large-scale power system. </LI> </UL> </P>
송전제약과 등가운전시간을 고려한 장기 예방정비계획 최적화에 관한 연구
신한솔(Hansol Shin),김형태(Hyoungtae Kim),이성우(Sungwoo Lee),김욱(Wook Kim) 대한전기학회 2017 전기학회논문지 Vol.66 No.2
Most of the existing researches on systemwide optimization of generator maintenance scheduling do not consider the equivalent operating hours(EOHs) mainly due to the difficulties of calculating the EOHs of the CCGTs in the large scale system. In order to estimate the EOHs not only the operating hours but also the number of start-up/shutdown during the planning period should be estimated, which requires the mathematical model to incorporate the economic dispatch model and unit commitment model. The model is inherently modelled as a large scale mixed-integer nonlinear programming problem and the computation time increases exponentially and intractable as the system size grows. To make the problem tractable, this paper proposes an EOH calculation based on demand grouping by K-means clustering algorithm. Network congestion is also considered in order to improve the accuracy of EOH calculation. This proposed method is applied to the actual Korean electricity market and compared to other existing methods.
A Study on the IP Transmission Stream for High-Definition Image Transmission
Hansol Joo,Seung-Jung Shin 한국인터넷방송통신학회 2021 Journal of Advanced Smart Convergence Vol.10 No.2
In order to broadcast 8K UHD, domestic broadcasting is upgrading production, operation, and transmission technologies in a new way that has various forms such as terrestrial broadcasting, IPTV, mobile, and streaming services. In order to overcome the existing SDI transmission technology that has reached its limit, new transmission technologies using ICT-based convergence such as IT, Network, IOT, and Big Data are developing. Internet Protocol(IP) transmission technology is an IT-based core protocol that transcends various broadcasting infrastructures. Therefore, it can be said that the technology for converting the broadcasting system based on IP is a natural one for preparing for 8K UHD in the future. In this paper, we propose an IP transmission system that adopts a network that can transmit 8K with hardware of 12G Serial Digital Interface (SDI), in order to prepare for the future broadcasting system according to the development of ALL IP interface technology.
Comparative Study of Negative Capacitance in Ferroelectric Capacitors
Hansol Ku,Changhwan Shin 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.2
Negative capacitance (NC) has received much attention as a solution to overcome the physical limit of sub-threshold slope (SS) of metal-oxidesemiconductor field-effect transistors (MOSFETs). With the help of a step-up internal voltage amplification by NC, sub-60-mV/decade steep switching MOSFET (or negative capacitance FET, NCFET) was experimentally demonstrated. In this work, the transient response of NC in a P(VDF0.75-TrFE0.25) organic ferroelectric capacitor is experimentally compared against that in a Pb(Zr, Ti)O₃ inorganic ferroelectric capacitor. It is confirmed that the RC time constant of the Pb(Zr, Ti)O₃ capacitor was smaller than that of the P(VDF0.75-TrFE0.25) capacitor owing to the low internal resistance of Pb(Zr, Ti)O₃.
Hansol Ku,Changhwan Shin 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.3
The transient response of the negative capacitance (NC) in a P(VDF0.75-TrFE0.25) ferroelectric capacitor is experimentally compared against that of a P(VDF0.50-TrFE0.50) ferroelectric capacitor. To measure first-hand the negative capacitance of the capacitor, a basic resistor-capacitor (RC) series circuit consisting of an external resistor and the ferroelectric capacitor was constructed. It was verified that the time duration of the NC could be adjusted based on the value of the external resistor. It was also confirmed that the transient response of the NC of the P(VDF0.75-TrFE0.25) ferroelectric capacitor versus that of the P(VDF0.50-TrFE0.50) ferroelectric capacitor was more sensitive to variation in the external resistor values. This is attributed to the reason that the polarization switching of P(VDF0.75-TrFE0.25) ferroelectric capacitor is faster than that of the P(VDF0.50-TrFE0.50) ferroelectric capacitor.
Development of a TPU/CNT/Cu Composite Conductive Filament with a High CNT Concentration
Hansol Kim,Hojin Yoo,Seungcheol Shin,Jungho Cho,Sang-Woo Han,In Hwan Lee 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.2
In this study, a flexible conductive filament was fabricated by mixing thermoplastic polyurethane (TPU), carbon nanotubes (CNTs), and Cu powder. A polymer extruder was used to disperse conductive materials in the TPU matrix. Because the dispersion of CNTs in polymers is difficult, the dispersion process was repeated several times for the homogeneity of the fabricated conductive filament. Cu powder with high electrical conductivity was additionally added to improve the electrical characteristics of the conductive polymer. As TPU generally has excellent ductility and durability, the fabricated filament can secure flexibility. The resistance was measured and compared according to the mixing ratio of CNT/Cu powder. Based on the obtained results, the resistance of the conductive filament decreased as the CNT and Cu powder contents were increased. The addition of metal powders, such as CNTs and Cu powder, however, reduced the ductility of TPU. Finally, the developed conductive filament was used to fabricate a simple closed photodiode circuit.
A Study on the Contents Security Management Model for Multi-platform Users
Hansol Joo,Seung-Jung Shin 한국인터넷방송통신학회 2021 Journal of Advanced Smart Convergence Vol.10 No.2
Today people adopt various contents from their mobile devices which lead to numerous platforms. As technology of 5G, IOT, and smart phone develops, the number of people who create, edit, collect, and share their own videos, photos, and articles continues to increase. As more contents are shared online, the numbers of data being stolen continue to increase too. To prevent these cases, an authentication method is needed to encrypt the content and prove it as its own content. In the report, we propose a few methods to secure various misused content with secondary security. A unique private key is designed when people create new contents through sending photos or videos to platforms. The primary security is to encrypt the “Private Key” with a public key algorithm, making its data-specific “Timeset” that doesn’t allow third-party users to enter. For the secondary security, we propose to use Message Authentication Codes(MACs) to certify that we have produced the content.